1. Field of the Invention
This invention relates to the use of specific heterocyclic hydrogen phosphonates as antiwear additives in functional fluids, and the compositions thereby obtained. More particularly, the invention relates to the use of spiro-bis-hydrogen phosphonate and cycloneopentyl glycol hydrogen phosphonate and related products. The functional fluids are particularly synthetic lubricants and/or water-based fluids (rather than petroleum-based products).
2. Prior Art
The use of antiwear additives in functional fluids is extremely old in the art. Spiro-bis-hydrogen phosphonate and cycloneopentyl glycol hydrogen phosphonate are both known in various physical forms. However, neither compound is now known to have been actually used as an antiwear additive in a non-petroleum based functional fluid.
Spiro-bis-hydrogen phosphonate (hereinafter "Compound A") is indexed by Chemical Abstracts Service (CAS) under the name pentaerythritol diphosphite and Register No. 2723-44-6. CAS has apparently indexed only three references, according to a computer search. These are discussed below.
Russian Pat. No. 476,267 describes spiro-bis-hydrogen phosphonate as being a useful intermediate for insecticides and flame-proofing agents. The patent includes a method of preparation that is quite similar to the method used herein. It gave a 100% yield of a white crystalline powder melting at 90.degree.-95.degree. C. (in contrast to about 170.degree. C. in Examples 1B-1D hereinafter).
The CAS reference CA65:10719c is apparently a miscite.
"Pentaerythritol Phosphite Condensation Polymers" by L. Friedman and H. Gould in Am. Chem. Soc., Div. Polymer Chem., Preprints 4(2), 98-101(1963)(Eng) is primarily directed to polymers intended for flame retardant applications. In general, "many of these polymers have interesting properties but were too unstable towards moisture to be effective as materials of construction". However, "they are quite effective as additives in stabilizing other polymer systems, such as polyethylene . . . against oxidative and thermal degradation". All of the polymers were prepared from raw materials including diphenyl pentaerythritol diphosphite, rather than pentaerythritol diphosphite. At least three of the references cited by Friedman and Gould are of interest. In particular, see U.S. Pat. No. 3,053,878 (Friedman and Gould); U.S. Pat. No. 3,047,608 (Friedman and Gould); and U.S. Pat. No. 2,847,443 (Hechenbleikner and Lanoue). However, they do not appear to disclose or suggest the invention claimed hereinafter.
Cycloneopentyl glycol hydrogen phosphonate (hereinafter "Compound B") is old in the art. Three U.S. Patents are discussed below.
U.S. Pat. No. 3,152,164 (Oswald) relates to the preparation of compounds such as Compound B by transesterification of a phosphite diester with a glycol. Oswald suggests that the cyclic organic phosphorus compounds of his invention will be of particular advantage due to their increased thermal and hydrolytic stability as petroleum additives themselves or can be used as starting materials for the preparation of additives (see Col. 2, lines 65-69).
U.S. Pat. No. 2,916,508 (McConnell) describes the preparation of Compound B (shown at Col. 2, line 10). The proposed enduses are merely insecticides, stabilizers for polyesters and artificial resins, fungicides, and other related uses.
U.S. Pat. No. 2,899,455 (Coover et al.) concerns derivatives of Compound B obtained by addition-type reactions. The derivatives are described as being useful as pesticides, plasticizers, solvents, flame-proofing agents and intermediates.
Essentially, nowhere does the now-known aforementioned prior art disclose or suggest that Compound A or Compound B or closely related compounds have utility in water-based functional fluids or synthetic functional fluids.